What does my doctor mean when he/she says metastatic breast cancer is not curable, but is treatable?
By “not curable” your doctor means that once breast cancer has spread to “distant” parts of the body like the bones, lung, liver or brain, no treatment or combination of treatments will be able to completely eradicate the disease. Although it may respond well to a given treatment, the cancer will in almost every case develop resistance to that treatment and eventually grow back and spread. In a very few patients, not more than one or two in a hundred, the cancer does not grow back after it is treated--and no one knows why.
When the cancer does progress another treatment is tried, and then when that treatment fails, another is tried, and so on. This is referred to as "lines" of treatment. Because of this repeated treatment failure and increasing resistance that usually develops, people with metastatic breast cancer will almost always end up dying of their disease, eventually. However, the disease is generally quite responsive to treatments, and there are many of them available that fight the cancer in different ways. Although treatment is usually continuous, symptoms and side effects can usually be managed successfully. As a result, many women with a diagnosis of metastatic breast cancer go on to live for a number of years, usually with very good quality of life. They can often continue working, raise their families and pursue normal activities for extended periods of time.
If it can’t be cured, what is the goal of treatment in metastatic disease?
The goal of treatment in metastatic disease is to control the disease, preventing progression for as long as possible, while still offering the patient the best possible quality of life. This means that close follow-up and good communication between doctor and patient are very important. Most oncologists attempt to treat metastatic breast cancer as if it were a chronic disease.
What factors determine how long an individual woman will live with the disease?
The biology of the cancer itself is probably the largest factor. Metastatic breast cancer is not one disease, but several. Cancers grow at different rates, spread in different ways, and respond to different kinds of treatments. For most patients, chemotherapy drugs are no longer the only choice. Targeted treatments are available for cancers that are hormone-sensitive, that is, ER and/or PR-positive, and for those that are HER2-positive. These treatments have made a difference in length of survival for patients in these groups, by offering additional, generally less toxic, treatment options.
For patients whose tumors do not overexpress these genes, chemotherapy remains the mainstay, and is often thought to be more effective in this patient group. Sensitivity to treatments plays a major role in length of survival, as does the speed of progression of her disease. An extensive length of time between primary breast cancer and recurrence can be a positive indicator. So can minimal metastatic disease confined to the bones. General health is an important factor, since a woman otherwise in good health will be more able to tolerate the treatments. There are certainly patterns of metastatic disease that are more or less aggressive.
Having said all this, it’s impossible for any doctor to predict how long a particular patient will live, and every oncologist who treats this disease has a number of patients in his or her practice who have long outlived their “expiration date.”